1. Field of the Invention
With respect to the classification of art as established in the United States Patent and Trademark Office the present invention pertains to the Class entitled, "Paper Manufacture" (Class 93) and to the subclass thereunder entitled, "Box machines refolding and/or opening - pivoted suction devices and methods" (subclass 53 SD and 53M)
2. Description of the Prior Art
Erecting cartons from a flat storage condition is, of course, well known and as an apparatus and method is shown in many machines and patents. In the present invention the flat cartons are presented to a supply hopper in a more-or-less vertical condition. Whereas in the related patents, above mentioned, the containers are advanced by an intermittently advanced toothed belt the present invention utilizes a reciprocated platform positioned in the supply chute. This platform is raised above a support frame during a forward stroke portion and is lowered below this support frame for the return stroke portion. By varying the length and frequency of stroke of the platform the cartons carried thereby are supplied in a sufficient amount to a delivery chute whereat the cartons are guided to and repose in a substantially horizontal stored condition.
Insofar as is known, prior art devices utilizing vacuum cups and swinging arms are quite limited in their ability to accept deviations in the size construction of the cardboard cartons. The present invention provides an escapement gate which accommodates variations in carton size construction much in excess of the feeding gates previously known or employed in carton erecting mechanisms.
Where the vacuum supply is achieved by moving a pneumatic cylinder, the initial vacuum is quite low during the beginning movement of the cylinder which provides this source of vacuum. This method of vacuum supply is particularly shown in U.S. Pat. No. 3,848,394, above-identified. In the present invention is provided a vacuum booster means to insure an adequate supply of vacuum to the suction cups carried on the arms as the cups are brought into engagement with the side of the folded carton to be erected. This carton is at the discharge end of the delivery chute and when a determined level of vacuum is achieved in the vacuum system provided by the movable pneumatic cylinder the initial assist is terminated with the larger level of vacuum provided by this cylinder.
In the present invention as in the prior art inventions, above-identified, from the storage chute the folded cartons are withdrawn one-at-a-time by commonly reciprocally rotatable arms, each of which carries a vacuum cup. These cups are pressed against the exposed lower side of the lowermost carton and with vacuum grip the carton to remove this carton from the chute and bring this carton to an erected condition in a transfer apparatus as described more fully in the above-identified patents.
As in the above-identified inventions, the present invention in the movement of the suction arms uses a lost motion for both the grasping movement for the carton and the movement for the release of the carton. This lost motion insures that the pull needed to remove the carton is achieved through a vacuum assist. When a desired vacuum is achieved the assist vacuum is terminated automatically.